Monoline policy

A monoline policy provides one kind of coverage: commercial general liability alone, workers' compensation, commercial auto, stand-alone property, professional liability. In ISO's commercial lines program each line has its own coverage part and forms, and "monoline" means you bought one part. The alternative is a commercial package policy, where two or more parts share a policy, or a business owner's policy, which bundles property and liability for smaller firms.

Some lines are almost always monoline. Workers' comp, commercial auto, professional liability, cyber and D&O sit on their own forms and are often written by specialty carriers, so even a business with a package program typically holds several monoline policies alongside it. Monoline also lets a buyer pick the strongest carrier for each line instead of accepting one insurer's average.

The trade-offs are practical. You lose the package credit insurers often give for combining lines. Renewal dates, claim contacts and underwriters multiply. And gaps and overlaps appear at the seams, for example when one carrier's property policy and another's liability form define the same loss differently. A broker who places monoline coverage should reconcile limits, deductibles and endorsements across policies. The guides on commercial package policies and Bundling business policies: BOPs, packages and multi-line accounts explain when each structure fits.